For instance, a window regulator including: a guide rail which extends vertically; a slider base which is supported by the guide rail to be movable up and down and by which a window glass is supported; a drive wire which is routed into a loop and moves the slider base up and down; a drive drum around which the drive wire is wound; and a drum housing which supports the drive drum is known as a window regulator.
When this type of window regulator is produced (assembled), it is absolutely necessary to perform a step of placing tension on (applying tension to) the drive wire with all the components of the window regulator (that include the guide rail, the slider base, the drive wire, the drive drum and the drive housing in the above described example) assembled.